Regulator system



May 12, 1931. E. GRAU 1,804,606

REGULATOR SYSTEM Filed Nov. '7, 1927 INVENTOR 2 r057 Grau Jami 06M A ATTORNEY Patented May 12, 1931 V UNITED STA S PATENTTOFFICE who, when A 3 no imam-rm, GERMANY, ASSIGNOR T0 WE enhances-1r ELECTRIC & m wherein G COMPANY, A oom'o'rmnon or r m" sYLvANfLA' Y moi-rims SYSTEM 7 Application met! ii'o'iiember 7 192?, erial R0.

' My invention relates to load-regulating systems -and more particularly to regulating systems for maintaining a predetermined constant and balanced load on a plurality of work device's. 1 3

j My invention has application in governing he-feeding of material to a plurality of wood grinders or the like driven from a common motor. In grinders using a single grinds'tone driven by a motor, the load on the'grinding motor is preferablykept approximately constant by regulating thelpressure with which the wo'o'd'is forced against the grindstone.

- Wherea grinding motor is 'used to drive a pair of grindstones, itis sufficient, so far as maintaining the load on the-grinding motor constant is concerned, to regulate the total presslires at the grindstones for constant load; It often happens, however, that the distribution of the load at the individual grindstones varies. If, at one grindstone, a particularly high friction resistance develops, owing to the stone engaging a-khot in the wood, "while the other grindstone encoimterscavities containe'd'within the woodbeing'fedto the stone, sothat the. grindstone is only in Contact with small portions of the wood, the resistance is very small. This imbalance in load on the V two grinding stones may cause the ground wood or pulp to show an undesirable degree of irregularity.

The present'invention contemplates provid*- ing regulators for the individual feed motors that are attested simultaneously but oppositely by changes in the division'of the load be rweeh the grinding wheels. I r y r I An object ofmy invention is, therefore, to provide a load=regulating "system for a motor driving a plurality of work devices with whicha plurality of feed motors are utilized to govern the load on the several devices, wherein the total load on the driving motor is kept substahtiallyeohstant and the load ratio on the several reed motors is maintained at a predetermined value.

My invention will be better understood by reference to the a'ooompan ying drawing in which the single figure illustrates an einbodii merit of myinvehtion. I Referring to the drawing; s il'j'riviiig inowr I 27, one of the differentially 281,48h'hd "in Germany November 11,1328."

is illustrated which may drive a pair of grindstones and is provided with a rotor =2 and a stator winding 3 that is connected to the sup ply conductors 4, 5 and 6. Two feed motors 7 and 8 which control the feed of the wood to the grihdstones in a well known manner are provided. The motors 7-a'nd 8 areprov-ided respectively, with rotor windings- 9 and 16 and with stator windings 11 and 12' that are connected, by conductors 13, 1 1 and 15 and 16, 17 and 18, tothe supply conductors 4, b and 6. The rotor windings 9 and 10 are com nested, respectively, to variable resistors or speed-controlling rheostats 19 and Qi'thataro operated by the pilot motors 22 and 23'. The pilot motor 22 is rovided with an armature winding '24 and differentially related field windings 25 and 26. The-pilot motor 23 is provided with similar armature and field windings 27, 28 and 29. V

Regulating relays 31 and 32 control the pilot motors 22 an'd2-3, respectively, thus governing the load on "the feed motors 7 and 8. The relays 31' and 32"comprise, respectively, electromagnet windings 33 and 34 and movable 'contact members 35 and '36 to be actuated thereb to close circuits through the armaturewindings and one'of the field windings of the pilot motors to operate them in theone or the other direction. The motors '22 and 23 are energized from direct-current supply conductors 37, 38. The circuit through the motor 2'2 is completed through conductor39, armature winding 24, one of the diiferentially related field windings 25 and 26, oontaot member 35 and conductor 41. The circuit of "the motor, 23 is completed through the oondii'ctor 39, armature winding related field windings 28 and 29, contact member 3'6'and s condoctor-42. v

The windings of'the relays 31 and 32 are energized from two souroes of power, the transformer43 and the transformer 44. The current transformer 43 is conneoted to be responsive to the load on the main drivi n motor 1. The transformer 44 isprovided Withtwo sec ondary windings 46 and 47 that are connected, respeetively,t o the relay wind: wand 3 and with I summon primary ion ratio of the motors arm 56 and a'variable resistor .57.

The resistors 55- and 57 are connected in parallel-circuit relation to each other and inv series with oneof the two conductors 58 and 59 that are connected between current' transformers 61 and 62 that are connected, respec tively, to be responsive to the current of the.

said motors 7 and 8.

The operation of the system is as follows: As the load upon the main or grinding motor 1 increases or decreases, the voltage produced by the current transformer 43- simi- I larly increases and decreases and varies the energization of the relays 31 and 32.". The c i r cllit fromthe transformer '43 may be traced throughconductor 48 to a p'oint49, through thejrfelay winding 33andthe secondaryt'rans' former. winding '46, connected in parallelcircuit relation, to the point 50, then through conductor 51 to thefpoint 52, through therelay winding 3.4and thesecondary transformer winding 47, connected 'i'n parallel circuit relation, tothe point ,53,';and through the cone ductor 54 backt'othe transformer 43. a i

, A variable resistor 63 isprovided, and connected across thecircuit from the transformer 43, to adjust the currrent values correspondingto the neutral position of the relays 31 and 32 and thereby to adjust the load to'be maintained on the motor 1., 1 v If jthe-lo ad'OILthe motor 1 is less'thanthe desired value,the;relays'31 and 32 will close a circuit throughthe pilot motors 22 and v23, respectively, operatingthe rheostats 19 and 21 inadirectionto increase the loads on the feed motorsy7 and 8. When" the load on {the driving motorf hasflncreased to thewdesired value, the relays 31 and '32 will be actuated the illustrated position to deenergiz'el the pilot-motors 2 2 and 23 If the load onthe driving motor 1 rises above the desired value, the relays 31 and 32will be actuated in the opposite direction to decrease the speed. of the feed motors 7-; and Sand thereby to decrease the load on the drivingmotor 1. H If the, loads on the feed motors7land 8 yaryltoget cr, the e willbfe n c rrent flow g through the-conductors 58. and;59,sincethe transformers 61 and 62 are so connected as. to ppo each; o er. If, however, the. load 7 and 8 varies,; causing itjCllIl'Bllt to flow through the primary winding 45;.of the transformer 44,; current will flow through the circuit of the transformer winding ;46; ,and the relay winding 33,,and

throughthe: circilitof the transformer wind:

ingl47 andcjthejrelaycwindingl34g The transformer, windings 46 and '47 are s'oconnebted to the relay windings, 33-,and 34,reSpectiVfilLthflt,asmltlfint flowsthrough further desirable to maintain the load on oneof the feed motors, greater or less than that of the,- other feed motors, this'may be done by varying the position of the contact arm 756,; thus varying the J current ratios, of

the transformers 61; and. 62: corresponding to zero current through the transformer winding 45;, a t i Many mo ifications may be madeeinithe circuits and apparatus illustrated without departingfrom the spirit of mylinventionrland I donot wish to be limited otherwise than by thescope of the appended claims. 1-; I claim-as myinvention:- .4 1. In an electricifeed-control system,.,a

plurality of work devices, a common driving motor for operating said work :devic es,separate: motors for feeding; the *work. to: said several work devices, aregulator for eachgof said feed motors comprising a'magnetwinding, a circuit for each a of said windings, means for energizing said windingsvin ace cordance with the load on said driving motor, and means for introducing voltages lnto'the circuits of said windings which vary in accordance with variations in the load :dis-' tribution on'said feedmotors. 7 241m feed-control system, two work devices, a common driving motor'for operating said work devices,.separate feed motors for feeding the work to saidwork devices, a regulator for each of said motors compris inga magnet winding,a circuit for each: of said windings,',means for energizing said windings in accordance with the load ons'aid driving motor, andmeans for varying the energization of each of said windings in'accordance with thegdifference infitheloads between said feed motors. r

, 3. In a feed-control system, a pair of work devices, a common driving motor for oper- 31 and 32 will cause an in- 1 ating' said work devices,- separate feed motors for'feedingthe' work to said work-devices,-a regulator forqea'ch of said feedmotors, acircuit for actuating said regulators, twovsources of energy for supplying said 'c1r- 7 cult, one of said sources being responsive to the load on the main motor andone of said sources being responsive to the difference in the loads between said feed motors-f Y 7 4. In a feed-controlsystem, a pair ofwork devices, a common driving motor for operating said work devices, separate feed mo? tors for feedingthe work to said work dovices, a regulator for each of said feed motors comprising a magnet winding, a circuit for each of said windings, means for energizing said windings in accordance with the load on said driving motor, and means for simultaneously and oppositely varying the energization of said windings upon changes in the division of load between said Work devices.

In testimony whereof, I have hereunto subscribed my name this l3th day ofOctober, 1927, at Berlin-Siemensstadt, Germany.

ERNST GRAU. 

